The serratus posterior superior muscle helps to: 1. Elevate the ribs: It assists in elevating the 2nd to 5th ribs, which helps in increasing the thoracic cavity volume during inspiration. 2. Assist in inspiration: By elevating the ribs, it aids in expanding the chest cavity, making it easier to breathe in. The serratus posterior superior muscle plays a role in supporting respiratory movements, particularly during deep or forced inspiration. The serratus posterior inferior muscle helps to: 1. Depress the ribs: It assists in depressing the 9th to 12th ribs, which helps in decreasing the thoracic cavity volume during expiration. 2. Assist in expiration: By depressing the ribs, it aids in reducing the chest cavity volume, making it easier to breathe out. The serratus posterior inferior muscle plays a role in supporting respiratory movements, particularly during forced expiration.
